Computed tomography (CT), magnetic resonance imaging (MRI), ultrasonography (US), bone scintigraphy, and conventional radiographs are important techniques in the detection, staging, and clinical management of pediatric solid tumors. The broad long-term objective of this proposal is to join a collaborative multicenter study group to compare the relative accuracy of the various imaging studies in patients with pediatric solid tumors to optimize staging and clinical management of these patients. Patients under 18 years of age presenting to the Mallinckrodt Institute of Radiology (MIR) with a mass (suspected neoplasm) will undergo CT, MRI, US, bone scintigraphy, and/or conventional skeletal radiography, according to the RDOG4 group-developed protocol. The results of the imaging studies will be tested for correlations with the results of surgery and pathologic examination to determine the relative sensitivity, specificity, and accuracy of each imaging method. It is hypothesized that MRI of the abdomen and marrow-bearing portions of the skeleton performed as a single examination is a sufficient initial staging method in children with neuroblastoma. The information to be provided by the proposed clinical investigation should provide a definitive test of this hypothesis. A candidate protocol for assessment of abdominal masses, shown to be of adrenal origin by ultrasound, is provided as an indication of our ability to develop plans for initial staging of pediatric solid tumors- neuroblastoma in this case.